Uplink transmission method and apparatus in cellular communication system

ABSTRACT

The present disclosure relates to a communication technique for fusing, with an IoT technology, a 5G communication system for supporting a higher data transfer rate than a 4G system, and a system therefor. The present disclosure may be applied to intelligent services, such as smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail businesses, security and safety-related services, on the basis of 5G communication technologies and IoT-related technologies. Disclosed is a setting method for an efficient uplink signal transmission of a terminal in a case where a plurality of waveforms are supported to efficiently operate an uplink in a next generation mobile communication.

PRIORITY

This application is a Continuation of U.S. patent application Ser. No.16/856,606, which was filed with the U.S. Patent and Trademark Office(USPTO) on Apr. 23, 2020, which is a Continuation of U.S. patentapplication Ser. No. 16/463,658, which was filed with the USPTO on May23, 2019, issued as U.S. Pat. No. 10,986,616 on Apr. 20, 2021, as aNational Phase Entry of PCT International Application No.PCT/KR2017/013078, which was filed on Nov. 17, 2017, and claims priorityto Korean Patent Application No. 10-2016-0156806, which was filed onNov. 23, 2016, the entire content of each of which is incorporatedherein by reference.

BACKGROUND 1. Field

The present invention relates to a wireless communication system and, inparticular, to a method and apparatus for transmitting/receiving asignal in a next generation mobile communication system.

2. Related Art

To meet the increased demand for wireless data traffic since thedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a “Beyond 4G Network” or a“Post LTE System”. Implementation of the 5G communication system inhigher frequency (mmWave) bands, e.g., 60 GHz bands, is being consideredin order to accomplish higher data rates. To decrease propagation lossof radio waves and increase the transmission distance, beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, analog beam forming, and large scale antennatechniques are being discussed for the 5G communication system. Inaddition, in the 5G communication system, there are developments underway for system network improvement based on advanced small cells, cloudRadio Access Networks (RANs), ultra-dense networks, device-to-device(D2D) communication, wireless backhaul, moving network, cooperativecommunication, Coordinated Multi-Points (CoMP), reception-endinterference cancellation, and the like. In the 5G system, Hybrid FSKand QAM Modulation (FQAM) and sliding window superposition coding (SWSC)as advanced coding modulation (ACM) and filter bank multi carrier(FBMC), non-orthogonal multiple access (NOMA), and sparse code multipleaccess (SCMA) as advanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving into theInternet of Things (IoT) where distributed entities, such as things,exchange and process information without human intervention. TheInternet of Everything (IoE), which is a combination of IoT technologyand Big Data processing technology through connection with a cloudserver, has emerged. As technology elements, such as “sensingtechnology”, “wired/wireless communication and network infrastructure”,“service interface technology”, and “security technology” have beendemanded for IoT implementation, recently there has been research into asensor network, Machine-to-Machine (M2M) communication, Machine TypeCommunication (MTC), and so forth. Such an IoT environment may provideintelligent Internet technology services that create new values forhuman life by collecting and analyzing data generated among connectedthings. The IoT may be applied to a variety of fields including smarthome, smart building, smart city, smart car or connected cars, smartgrid, health care, smart appliances, and advanced medical servicesthrough convergence and combination between existing InformationTechnology (IT) and various industrial applications.

In line with these developments, various attempts have been made toapply the 5G communication system to IoT networks. For example,technologies such as a sensor network, Machine Type Communication (MTC),and Machine-to-Machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RadioAccess Network (RAN) as the above-described Big Data processingtechnology may also be considered to be an example of convergencebetween the 5G technology and the IoT technology.

Recent researches are devoted to support multiple waveforms foroperating uplink efficiently in a next generation mobile communicationsystem, which requires a method for efficiently scheduling uplink signaltransmissions of terminals. For efficient data transmission, there is aneed of a method for determining a size of a code block (CB) andtransmitting/receiving data based on the determined CB size.

SUMMARY

The present invention proposes a method for a terminal in the state ofperforming initial attachment or in a connected state to determine awaveform the use in an uplink transmission autonomously and a method andapparatus for a base station to configure the waveform for use by theterminal in the uplink transmission. The present invention provides amethod for segmenting a transport block (TB) by the maximum CB size thatis reported by a terminal or configured by a base station.

In accordance with an aspect of the present invention, a method isprovided for a terminal in a wireless communication system. The methodincludes determining a maximum code block size based on a transportblock size and modulation and coding scheme (MCS) information;determining a number of code blocks for the transport block; andsegmenting the transport block into the determined number of codeblocks.

In accordance with another aspect of the present invention, a method isprovided for a base station in a wireless communication system. Themethod includes determining a maximum code block size based on atransport block size and MCS information; determining a number of codeblocks for the transport block; and segmenting the transport block intothe determined number of code blocks.

In accordance with another aspect of the present invention, a terminalis provided for use in a wireless communication system. The terminalincludes a transceiver; and a controller configured to determine amaximum code block size based on a transport block size and MCSinformation, determine a number of code blocks for the transport block,and segment the transport block into the determined number of codeblocks.

In accordance with yet another aspect of the present invention a basestation is provided for use in a wireless communication system. The basestation includes a transceiver; and a controller configured to determinea maximum code block size based on a transport block size and MCSinformation, determine a number of code blocks for the transport block,and segment the transport block into the determined number of codeblocks.

The present invention is advantageous in terms that a terminal and abase station are capable of performing uplink transmission/receptionefficiently in a situation where multiple waveforms are in use foruplink. The present invention is also advantageous in terms of reducingunnecessary data transmission based on efficiently data transmissionbetween a terminal and a base station.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of certainembodiments of the disclosure will be more apparent from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a diagram illustrating a configuration of a transmitter of abase station for transmitting a downlink signal in a legacy LTE system;

FIG. 2 is a block diagram illustrating a configuration of an OFDM signalgenerator for transmitting a downlink signal in a legacy LTE system;

FIG. 3 is a diagram illustrating a configuration of a transmitter of aterminal for transmitting an uplink signal in a legacy LTE system;

FIG. 4 is a block diagram illustrating a configuration of a DFT-S-OFDMsignal generator for generating a DFT-S-OFDM signal being considered asa waveform for uplink in the legacy LTE system and 5G communicationsystem;

FIG. 5 is a signal flow diagram illustrating a random access procedurebetween a terminal and a base station in a legacy LTE system to helpexplain a random access being considered in the present invention;

FIG. 6 is a block diagram illustrating a configuration of thetransmitter of the base station according to an embodiment of thepresent invention;

FIG. 7 is a block diagram illustrating a configuration of the receiverof the terminal according to an embodiment of the present invention;

FIG. 8 is a diagram illustrating a basic time-frequency resourcestructure for transmitting downlink data or control channels in an LTEsystem;

FIG. 9 is a diagram illustrating a basic time-frequency resourcestructure for transmitting uplink data or control channels in an LTE-Asystem;

FIG. 10 is a diagram illustrating frequency-time resources allocated fortransmitting data of eMBB, URLLC, and mMTC services in a communicationsystem;

FIG. 11 is a diagram illustrating frequency-time resources allocated fortransmitting data of eMBB, URLLC, and mMTC services in a communicationsystem;

FIG. 12 is a diagram illustrating a procedure for segmenting a transportblock into multiple code blocks and attaching a CRC to the code blocks;

FIG. 13 is a diagram illustrating a coding structure to which an outercode is applied according to an embodiment of the present invention;

FIG. 14 is a block diagram illustrating channel coding processes withand without applying an outer coder according to an embodiment of thepresent invention;

FIG. 15 is a flowchart illustrating a procedure for data communicationusing a maximum CB size configured between a base station and a terminalaccording to embodiment 2 of the present invention;

FIG. 16 is a flowchart illustrating an operation of a transmitteraccording to embodiment 2-1 of the present invention;

FIG. 17 is a flowchart illustrating an operation of a receiver accordingto embodiment 201 of the present invention;

FIG. 18 is a diagram illustrating a structure of a TB that is segmentedinto CBs, to which filler bits are added at their beginnings, accordingto an embodiment of the present invention;

FIG. 19 is a diagram illustrating a structure of a TB that is segmentedinto CBs, to which filler bits are added at their ends, according to anembodiment of the present invention;

FIG. 20 is a block diagram illustrating a configuration of a terminalaccording to an embodiment of the present invention; and

FIG. 21 is a block diagram illustrating a configuration of a basestation according to an embodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention are described in detailwith reference to the accompanying drawings. Detailed description ofwell-known functions and structures incorporated herein may be omittedto avoid obscuring the subject matter of the present invention. Further,the following terms are defined in consideration of the functionality inthe present invention, and may vary according to the intention of a useror an operator, usage, etc. Therefore, the definition should be made onthe basis of the overall content of the present specification.

Advantages and features of the present invention and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of exemplary embodiments and theaccompanying drawings. The present invention may, however, be embodiedin many different forms and should not be construed as being limited tothe exemplary embodiments set forth herein; rather, these exemplaryembodiments are provided so that this invention will be thorough andcomplete and will fully convey the concept of the invention to thoseskilled in the art, and the present invention will only be defined bythe appended claims. Like reference numerals refer to like elementsthroughout the specification.

It will be understood that each block of the flowcharts and/or blockdiagrams, and combinations of blocks in the flowcharts and/or blockdiagrams, can be implemented by computer program instructions. Thesecomputer program instructions may be provided to a processor of ageneral-purpose computer, special purpose computer, or otherprogrammable data processing apparatus, such that the instructions thatare executed via the processor of the computer or other programmabledata processing apparatus create means for implementing thefunctions/acts specified in the flowcharts and/or block diagrams. Thesecomputer program instructions may also be stored in a non-transitorycomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the non-transitorycomputer-readable memory produce articles of manufacture embeddinginstruction means that implement the function/act specified in theflowcharts and/or block diagrams. The computer program instructions mayalso be loaded onto a computer or other programmable data processingapparatus to cause a series of operational steps to be performed on thecomputer or other programmable apparatus to produce a computerimplemented process such that the instructions that are executed on thecomputer or other programmable apparatus provide steps for implementingthe functions/acts specified in the flowcharts and/or block diagrams.

Furthermore, the respective block diagrams may illustrate parts ofmodules, segments, or codes including at least one or more executableinstructions for performing specific logic function(s). Moreover, itshould be noted that the functions of the blocks may be performed in adifferent order in several modifications. For example, two successiveblocks may be performed substantially at the same time, or may beperformed in reverse order according to their functions.

According to various embodiments of the present invention, the term“module”, means, but is not limited to, a software or hardwarecomponent, such as a Field Programmable Gate Array (FPGA) or ApplicationSpecific Integrated Circuit (ASIC), which performs certain tasks. Amodule may advantageously be configured to reside on the addressablestorage medium and configured to be executed on one or more processors.Thus, a module may include, by way of example, components, such assoftware components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables. The functionalities of the components and modules may becombined into fewer components and modules or further separated intomore components and modules. In addition, the components and modules maybe implemented such that they execute one or more CPUs in a device or asecure multimedia card. According to various embodiments of the presentinvention, a module may include one or more processors.

Embodiment 1

The mobile communication system has evolved to a high-speed,high-quality packet data communication system (such as High Speed PacketAccess (HSPA), LTE (or evolved universal terrestrial radio access(E-UTRA)), LTE-Advanced (LTE-A), and LTE-Pro defined in 3^(rd)Generation Partnership Project (3GPP), High Rate Packet Data (HRPD)defined in 3^(rd) Generation Partnership Project-2 (3GPP2), Ultra MobileBroadband (UMB), and 802.16e defined in IEEE)) capable of providinghigh-speed high-quality packet data services beyond the earlyvoice-oriented services.

The LTE system as one of the representative broadband wirelesscommunication systems uses orthogonal frequency division multiplexing(OFDM) in the downlink (DL) and discrete Fouriertransform-spread-OFDM-based (DFT-S-OFDM-based) single carrier frequencydivision multiple access (SC-FDMA) in the uplink (UL). The term “uplink”denotes a radio link for transmitting data or control signals from aterminal that is interchangeably referred to as user equipment (UE) andmobile station (MS) to a base station (BS) that is interchangeablyreferred to as evolved node B (eNB), and the term “downlink” denotes aradio link for transmitting data or control signals from a base stationto a terminal. Such multiple access schemes are characterized byallocating the time-frequency resources for transmitting user-specificdata and control information without being overlapped with each other,i.e., maintaining orthogonality, so as to distinguish amonguser-specific data and control information.

As a next generation communication system after LTE, the 5Gcommunication system should be designed to meet various requirements ofservices demanded by users and service providers. The services supportedby 5G systems may be categorized into three categories: enhanced mobilebroadband (eMBB), massive machine type communications (mMTC), andultra-reliable and low-latency communications (URLLC).

The eMBB aims to provide exceptionally high data rate in comparison withthose supported by the legacy LTE, LTE-A, and LTE-A Pro. For example,the eMBB aims to increase the peak data rate up to 20 Gbps in DL and 10Gbps in UL per base station. Simultaneously, it aims to increase theuser-perceived data rate. In order to meet such requirements, it isnecessary to improve signal transmission/reception technologiesincluding multi-input multi-output (MIMO) technique. The data raterequirements for the 5G communication systems may be met by use of afrequency bandwidth broader than 20 MHz in the frequency band of 3 to 6GHz or above 6 GHz instead of the current LTE band of 2 GHz.

Meanwhile, the mMTC is considered to support application services forInternet of Things (IoT). In order to provide mMTC-based IoT applicationservices effectively, it is required to secure massive access resourcesfor terminals within a cell, improve terminal coverage and battery lifespan, and reduce device manufacturing cost. The IoT services should bedesigned to support a large amount of terminals (e.g., 1,000,000terminals/km²) within a cell in consideration by the nature of the IoTterminals that are attached to various sensors and devices for providinga communication function. By the nature of the IoT services, the mMTCterminals are likely to be located in coverage holes such as basement ofa building, which requires broader coverage in comparison with otherservices being supported in the 5G communication system. The mMTCterminals that are characterized by their low prices and batteryreplacement difficulty should be designed to have very long batterylifetime.

Finally, the URLLC is targeted for mission-critical cellular-basedcommunication services such as remote robot and machinery control,industrial automation, unmanned aerial vehicle, remote health care, andemergency alert services that are requiring ultra-low latency andultra-high reliability. For example, a URLLC service needs to meet therequirements of air-interface latency lower than 0.5 ms and packet errorrate equal to or less than 10′. In this respect, in order to support theURLLC services, the 5G system has to support transmit time intervals(TTI) shorter than those of other services and assign broad resources inthe frequency band.

As described above, the 5G communication system should be designed tosupport the different requirements for various services and scheduleuplink transmissions in consideration of the different requirements. Fora terminal located at the center of a micro cell or a macro cell wherethe channel condition or signal-to-interference-plus-noise ratio (SINR)is relatively good, it is preferred to maximize the data rate of theterminal. Meanwhile, for the case of a terminal located at an edge ofthe macro cell where the channel condition or SINR is bad, it ispreferred to secure coverage. The LTE system employs DFT-S-OFM-basedwaveforms in uplink. However, in the 5G communication system, both theOFDM and DFT-S-OFDM are considered for uplink transmission to optimizethe coverage and data rated in adaptation to the situation of theterminal.

FIG. 1 is a diagram illustrating a configuration of a transmitter of abase station for transmitting a downlink signal in a legacy LTE system.

As shown in FIG. 1 , the transmitter of the base station fortransmitting an LTE downlink signal includes scramblers 100, modulationmappers 110, a layer mapper 120, a precoder 130, resource elementmappers 140, and OFDM signal generators 150.

The scramblers 100 receive data encoded with a forward error correctioncode from an upper layer. Here, the forward error correction code-basedencoding is performed for detecting and correct potential bit errors incommunication between a terminal and a base station by encoding a bitstring with a convolutional code, a turbo code, or a low density paritycheck code (LDPC). The scrambler 100 scrambles an encoded input datastream to eliminate influence of an inter-cell interference. Thetransmitter of the base station may include multiple scramblers 100 forprocessing multiple codewords 160 from the upper layer. After beingscrambled, the codewords 160 are input to the modulation mappers 110.

The modulation mappers 110 perform modulation for transmitting basebandcodewords efficiently over an RF. The modulation mappers 110 modulatethe input codewords 160 into binary phase shift keying (BPSK),quadrature phase shift keying (QPSK), or quadrature amplitude modulation(QAM) symbols according to an upper layer configuration.

The layer mapper 120 maps the modulated symbols to layers properlyaccording to a transmission mode. The precoder 130 performs precoding onthe layer-mapped signals according to the transmission mode. Thepre-coded symbols are transferred to the resource element mappers 140corresponding to respective antenna ports according to a number ofantenna ports 170.

The resource element mapper 140 map the pre-coded symbol to resourceelements on time and frequency resources as scheduled by a scheduler perterminal. The signals mapped to the corresponding resource elements bythe resource element mapper 140 are input to the OFDM signal generators150, which convert the input signals to OFDM signals, which pass throughan digital-to-analog converter (DAC) and an RF unit and then aretransmitted by the antenna.

FIG. 2 is a block diagram illustrating a configuration of an OFDM signalgenerator for transmitting a downlink signal in a legacy LTE system.

In FIG. 2 , the OFDM signal generator includes an inverse fast Fouriertransform unit (IFFT) 210 and a cyclic prefix (CP) inserter 220. TheIFFT 210 performs an inverse Fourier transform on an input symbol X(k).The symbol X(k) 200 is identical with the time and frequency regionsymbol mapped to corresponding resources as scheduled by a base stationas shown in FIG. 1 . Typically, the IFFT 100 has a size of 2^(N) (N is anatural number greater than 1). Typically, the size of the IFFT 210 isgreater than K (K is the number of X(k) input to the IFFT 210), and2^(N)-K inputs of the 2^(N) inputs for the corresponding carriers arefilled with “0” values.

The CP inserter 220 inserts a CP to the IFFT'ed time domain signals togenerate signals robust to a multipath channel. A length of the CP isdetermined according to a delay spread of the multipath channelexperienced by a terminal. The CP-inserted signal x(n) may pass througha DAC and an RF module and then be transmitted to the terminal via anantenna.

The OFDM signal of FIG. 2 is generated by Equation 1.

$\begin{matrix}{{{x(n)} = {\frac{1}{\sqrt{N}}{\sum\limits_{k = 0}^{K - 1}{{X(k)} \cdot e^{j2\min/N}}}}},{n = {- N_{CP}}},{\ldots 0},{\ldots\left( {N - 1} \right)}} & \left\lbrack {{Equation}1} \right\rbrack\end{matrix}$

Here, X(k) denotes a QAM symbol to be OFDM-modulated, and x(n) denotes atime domain signal OFDM-modulated as described with reference to FIG. 1. In Equation 1, N denotes the size of IFFT, and N_(CP) denotes thelength of a CP being inserted to the transmit signal to generate theOFDM signal robust to the multipath channel. In Equation 1, K denotesthe size of a frequency domain signal X(k).

Typically, the OFDM signal generated by Equation 1 as described withreference to FIGS. 1 and 2 has advantages as follows in comparison withthe a single carrier-based transmission system.

The OFDM-based communication system is advantageous in terms ofcompensating the influence of multi-path fading effect caused bymulti-path delays between a transmitter and a receiver with a one-tapequalizer by dividing a broad frequency band for a mobile communicationsystem into a plurality of narrowband subcarriers and transmittingsignals on the respective subcarriers. It is also advantageous to beable to effectively cancel an inter-symbol interference (ISI) caused bymulti-path delays by inserting the CP. For these reasons, it is knownthat the OFDM is superior to the single carrier-based DFT-S-OFDM in datarate.

Unlike the LTE system in which the OFDM is used only for uplink, it isconsidered to use OFDM waveforms for both the uplink and downlink in the5G communication system. It the OFDM is used in uplink, this may improvethe uplink data rate and make it possible to cancel the interferencecaused uplink signals transmitted by terminals located in neighboringcells to the downlink signal being received by the terminal in a timedivision duplexing (TDD) system.

FIG. 3 is a diagram illustrating a configuration of a transmitter of aterminal for transmitting an uplink signal in a legacy LTE system.

In FIG. 3 , the transmitter of the terminal for transmitting an LTEuplink signal includes scramblers 300, modulation mappers 310, a layermapper 300, transform precoders 330, a precoder 340, resource elementmappers 350, and SC-FDMA signal generators (OFDM signal generators) 360.

The scramblers 100 receive data encoded with a forward error correctioncode from an upper layer. Here, the forward error correction code-basedencoding is performed for detecting and correct potential bit errors incommunication between a terminal and a base station by encoding a bitstring with a convolutional code, a turbo code, or a LDPC. The scrambler100 scrambles an encoded input data stream to eliminate influence of aninter-cell interference. The transmitter of the terminal may includemultiple scramblers 300 for processing multiple codewords 370 from theupper layer.

After being scrambled, the codewords 370 are input to the modulationmappers 310. The modulation mappers 310 perform modulation fortransmitting baseband codewords efficiently over an RF. The modulationmappers 310 modulate the input codewords 370 into BPSK, QPSK, or QAMsymbols according to an upper layer configuration.

The layer mapper 320 maps the modulated symbols to layers properlyaccording to a transmission mode. The layer mapped signal is input to atransform precoder 330 for applying DFT-S-OFDM. The signal input to thetransform precoders 330 are converted by Equation 2.

$\begin{matrix}{{{x_{dft}(n)} = {\frac{1}{\sqrt{M}}{\sum\limits_{i = 0}^{M - 1}{{X(i)} \cdot e^{{- j}2\min/M}}}}},{n = 0},{\ldots\left( {M - 1} \right)}} & \left\lbrack {{Equation}2} \right\rbrack\end{matrix}$

Here, X(i) denotes an output symbol of the layer mapper 320, andx_(dft)(n) denotes an output signal of the transform precoders 330 ofFIG. 3 . In Equation 2, M denotes a size of the DFT precoder performingDFT precoding.

The output signals of the transform precoders 330 are input to theprecoder 340 according to a transmission mode. The pre-coded symbols areinput to the resource element mappers 350 corresponding to respectiveantenna ports according to the number of antenna ports 380. The resourceelement mappers 350 maps the pre-coded symbol to resource elements ontime and frequency resources according to uplink scheduling informationfrom the base station. The signals mapped to the corresponding resourceelements by the resource element mappers 350 are input to the SC-FDMAsignal generators 360, which convert the input signals to SC-FDMAsignals, which pass through a DAC and an RF unit and then aretransmitted by the antenna.

FIG. 4 is a block diagram illustrating a configuration of a DFT-S-OFDMsignal generator for generating a DFT-S-OFDM signal being considered asa waveform for uplink in the legacy LTE system and 5G communicationsystem.

As shown in FIG. 4 , the DFT-S-OFDM signal generator includes a DFTprecoder 410, an IFFT 420, and a CP inserter 430. The DFT precoder 410performs a DFT operation on the input symbol X(k) 400. The DFT precodingmay be performed by Equation 2. In FIG. 4 , the DFT precoder 410 is acomponent identical in function with the transform precoder 330. Theoutput signal of the DFT precoder 410 is input to the IFFT 420, whichperforms inverse Fourier transform on input signal. Typically, the IFFT420 has a size of 2N (N is a natural number greater than 1). The size ofthe IFFT 420 is greater than M (M is the size of the output signalx_(dft)(n) of the DFT precoder 410), 2^(N)-M inputs of the 2^(N) inputsto the IFFT 420 are filled with “0” values. The IFFT operation may beimplemented with Equation 1.

The CP inserter 430 inserts a CP to the IFFT'ed time domain signals togenerate signals robust to a multipath channel. A length of the CP isdetermined according to a delay spread of the multipath channelexperienced by a terminal. The CP-inserted signal x(n) 440 may passthrough a DAC and an RF module and then be transmitted to the basestation via an antenna.

Typically, the DFT-S-OFDM signal generated as described with referenceto FIG. 4 has a drawback of a low data rate in comparison with that ofthe OFDM-based signal. However, the DFT-S-OFDM signal generation methodguarantees a low peak-to-average-power-ratio (PAPR) because it uses anadditional DFT precoder unlike the OFDM-based signal generation method.For this reason, the DFT-S-OFDM signal is advantageous in terms ofhaving an uplink coverage larger than that of the OFDM signal.

In summary, the OFDM is capable of providing terminals located within amicro cell or around the cell center of a macro cell with a high uplinkdata rate. Meanwhile, the DFT-S-OFDM is capable of providing terminalslocated at an edge of the macro cell or having a poor SINR with arelatively large coverage.

Because the OFDM and the DFT-S-OFDM are complementary to each other inview of uplink data rate and coverage, it is considered to employ boththe two waveforms in the 5G communication system. In order to accomplishthis goal, the 5G communication system standardization is progressed ina way of allowing a transmitter of a terminal to support both uplinkOFDM and DFT-S-OFDM signal transmissions and implementing a base stationto support any or both of the OFDM and DFT-S-OFDM signal transmissionsselectively. There is therefore a need of a method for the base stationto configure whether to use the OFDM and/DFT-S-OFDM to a specificterminal or all terminals located within a cell for communication and/ora method for a terminal to autonomously determine a waveform to be usedfor uplink transmission.

The present invention proposes a method for configuring a waveform foruse in communication to a terminal in a 5G communication systemsupporting two waveforms in uplink as described above. In detail, thepresent invention proposes a method for a base station configure aspecific waveform to a terminal and a method for the terminal toestimate the waveform autonomously for use in uplink transmission forsituations where the terminal is supposed to transmit an uplink signalin an initial access procedure and as scheduled in the state of beingconnected to a base station. The present invention also proposes anuplink transmission operation of a terminal to accomplish the abovemethods.

Embodiment 1-1

Embodiment 1-1 of the present invention is directed to a method fordetermining a waveform to be used by a terminal in an initial accessprocedure.

FIG. 5 is a signal flow diagram illustrating a random access procedurebetween a terminal and a base station in a legacy LTE system to helpexplain a random access being considered in the present invention.

In FIG. 5 , the base station 500 transmits a synchronization signal andsystem information, as denoted by reference numbers 520 and 530, inorder for the terminal 510 in the idle or connected state within a cellto achieve synchronization and obtain system information. The systeminformation 530 may be transmitted via a physical broadcast channel(PBCH) or a physical downlink shared channel (PDSCH) configured forsystem information transmission.

The terminal 510 achieves time and frequency synchronizations with thebase station and ascertain a cell number (cell identity) based on thesynchronization signal 520 transmitted by the base station 500. Thesynchronization signal may include a primary synchronization signal(PSS) and a second synchronization signal (SSS) in use for the LTEsystem or be a combination of them with an extra synchronization signal.The system information 530 may be used to transmit system informationnecessary for use in accessing the base station and its cell. Examplesof the system information may include information necessary for use inrandom access of the terminal.

After receiving the synchronization signal 520 and the systeminformation, the terminal 510 may transmit a random access preamble asdenoted by reference number 540. In the legacy LTE system, the terminal510 may transmit the random access preamble 540 based on time andfrequency transmission resource information for transmitting the randomaccess preamble 540 that is acquired from the system information 530.The random access preamble-transmission time and frequency resources areallocated at a predetermined interval and, if it is determined totransmit a random access preamble, the terminal may transmit thepreamble on the random access preamble transmission resources appearingafter the determination. The base station 500 attempts to detect randomaccess preambles transmitted by the terminals on the random accesspreamble transmission resources it has configured. Typically, the randomaccess preamble may be identified by time, frequency, and code; in theLTE system, it is possible to identify a terminal by a terminal-specificcode sequence.

If the base station 500 detects a random access preamble including aspecific code sequence, it transmits to the corresponding terminal, atstep 550, a random access response in response to the preamble. Theterminal 510 which has transmitted the random access preamble attemptsto receive the random access response at step 550 during a predeterminedtime period after transmitting the random access preamble. The randomaccess response received at step 550 may include resource allocationinformation, uplink timing control information, and uplink power controlinformation for use by the terminal that has transmitted the randomaccess preamble to transmit uplink data.

Upon receipt of the random access response, the terminal 550 maytransmit layer2 and/or layer3 message information to the base station,at step 550, according to the uplink resource allocation informationincluded in the random access response. Here, the terminal may transmitthe Layer2/Layer3 message 560 via a physical uplink shared channel(PUSCH). The terminal may use the information acquired from the randomaccess response 550 for transmitting the Layer2/Layer3 messageinformation 560 to the base station.

Upon receipt of the Layer2/Layer3 message 560, the base station maytransmit, at step 570, a collision resolution message in reply. Thecollision resolution message is transmitted for resolving a collisionthat may occur in the random access procedure. That is, in the casewhere multiple terminals transmit random access preambles with the samecode sequence at step 540, they transmit the Layer2/Layer3 message onthe same uplink resources, which causes a collision. Accordingly, thecollision resolution message being transmitted at step 570 is scrambledwith a unique identifier included in the properly received Layer2/Layer3message among the Layer2/Layer3 messages transmitted by the multipleterminals such that only the terminal selected by the base stationreceives the collision resolution message.

The random access procedure depicted in FIG. 5 may be identically usedin the 5G communication system. In the random access procedure depictedin FIG. 5 , the terminal has to transmit the uplink L2/L3 message uponreceipt of the random access response. The waveform for use in uplinksignal transmission of the terminal before the receipt of configurationinformation on a new waveform as a consequence of the random accessprocedure with the base station after the receipt of the random accessresponse is determined as follows.

The first method is for the terminal that has received a random accessresponse in the initial access procedure to always use aDFT-S-OFDM-based waveform. That is, this may be expressed that theterminal uses DFT precoding in addition to the OFDM-based waveform. TheDFT-S-OFDM or DFT precoding-based OFDM may be applied to both thephysical uplink control channel (PUCCH) and PUSCH being transmitted fromthe terminal the base station.

Because the base station has no channel status information or referencesignal received power (RSRP) or reference signal received quality (RSRQ)information reported by the terminal in the initial access procedure, itcannot determine a waveform suitable for the corresponding terminal.Accordingly, it may be preferred to use the DFT-S-OFDM (or DFTprecoding-based OFDM) for transmitting PUSCH and PUCCH in considerationof the worst situation of the terminal in the initial access procedureas in the first method. It may not inevitable to use OFDM in the initialaccess procedure during which the terminal needs not use a high datarate for uplink data transmission to access to the base station. Theterminal has to use the DFT-S-OFDM-based waveform for PUSCH and PUCCHtransmission before receiving new waveform configuration information viaradio resource control (RRC) connection setup.

The first method is advantageous in that the base station needs nottransmit an additional signal notifying the terminal of a waveform to beused and disadvantageous in that the base station should have a receiverthat is always capable of receiving DFT-S-OFDM signals. In order toprovide a degree of freedom for base station implementation, it may bepossible to consider following methods.

The second method is for the base station to notify the terminal locatedwithin a cell of the waveform to be used in the initial access procedurevia system information. The base station may also notify the terminalwhether to apply DFT precoding in addition to use of the OFDM-basedwaveform for transmitting PUSCH and PUCCH in the initial accessprocedure. Similar to the LTE system, the 5G communication system may bedesigned to configure multiple system information according to theirimportance and acquisition order. The system information is conveyed ina master information block that is supposed to be received after theterminal achieves synchronization with the base station and completes acell search and in multiple system information blocks that are supposedto be received subsequently.

The base station may notify the terminal of the waveform for use inPUSCH and PUCCH transmissions using a 1-bit field included in the masterinformation block. The base station may also notify the terminalslocated within the cell whether DFT precoding is necessary in additionto the use of the OFDM-based waveform for transmitting PUSCH and PUCCHusing a 1-bit field included in the master information block. In orderto make the above configuration, the master information block mayinclude a field indicating the waveforms for the PUCCH and PUSCH incommon or two fields indicating the waveforms for the PUCCH and PUSCHrespectively. For example, the waveform information field of the masterinformation block may be set to 0 for indicating no application of DFTprecoding and 1 for indicating application of DFT precoding to transmitPUSCH.

The base station may notify the terminal located within the cell of thewaveform to be used using a 1-bit field included in a system informationblock. The base station may also notify the terminal located within thecell whether to use the DFT precoding in addition to the OFDM waveformusing a 1-bit field. It may be possible to use 1 bit to indicate thewaveform to be used for PUSCH and PUCCH in common or 2 bits to indicaterespective waveforms to be used for PUSCH and PUCCH. The correspondinginformation may be included in the system information block associatedwith random access among multiple system information blocks. Forexample, in the system information block, the waveform information fieldis set to 0 to instruct the terminal to transmit PUSCH withoutapplication of DFT precoding and 1 to instruct the terminal to transmitPUSCH with application of DFT precoding.

If the waveform for use in uplink transmission during the initial accessprocedure is configured to the terminal, the terminal has to transmituplink signals with the waveform configured by the second method until anew terminal-specific waveform is configured via an RRC connectionsetup. If whether to perform DFT precoding on the uplink signal to betransmitted in the initial access procedure is configured to theterminal by the second method, terminal may apply the DFT precoding ornot as configured by the second method until a new terminal-specificwaveform is configured via an RRC connection setup.

The second method gives a high degree of freedom for the base station toconfigure the uplink waveform of the terminal and apply the DFTprecoding in comparison with the first method. However the second methodis not proper for the case where the terminals have different coveragesor different requirements because a common waveform is configured to theterminals located in the cell. In order to overcome this problem, it maybe possible to consider a third method that allows configuring thewaveform for use in uplink transmission or whether to use DFT precodingin the initial access procedure per terminal.

The third method is for the base station to notify the terminal locatedwithin a cell of the waveform to be used via a random access responsebeing transmitted in the case where the terminal transmits PUSCH inuplink to the base station in the initial access procedure. In the casewhere the terminal transmits the PUSCH in uplink to the base station inthe initial access procedure, the base station may configure whether touse the DFT precoding to the terminal via the random access response. Asdescribed above, the random access response includes resource allocationinformation (e.g., modulation and coding scheme and time and frequencyresources size) and a power control mode for uplink signal transmissionfrom the terminal to the base station. It may also be possible toindicate the waveform for use by the terminal in uplink signaltransmission using 1 bit. It may also be possible to indicate whether touse the DFT precoding using 1 bit. The waveform field may consist of 1bit and the wave information field may, by way of example, be set to 0for indicating use of OFDM and 1 for use of DFT-S-OFDM.

The fourth method is for the terminal to infer the waveform to be usedfrom the resource allocation information included in the random accessresponse instead of adding a field indicating the uplink waveform in therandom access response as in the third method.

In the fourth method, the terminal infers the waveform for use in aPUSCH transmission from the resource allocation information in the casewhere the base station notifies all terminals located within the cellthat it supports both the two waveforms via the system information; as afirst approach, it may be proposed to associate the waveform with theMCS assigned to the terminal. If the terminal is located at a cell edgewhere the SINR is too low to secure coverage, it is preferred to use alow MCS. If the terminal is located around the center of the cell or thecell is small, it is preferred to transmit uplink signals using a highMCS. The terminal is capable of inferring the waveform to be used fromthe MCS as resource allocation information included in the random accessresponse. The terminal may also infer whether the DFT precoding isapplicable to the OFDM-based waveform from the MCS as the resourceallocation information included in the random access response. Table 1is an MCS table that is used in the LTE system. In the fourth method ofembodiment 1-1 of the present invention, it is also proposed topreconfigure to use the DFT-S-OFDM or the OFDM according to the MCSindex in the 5G communication system. It is also proposed to predefinewhether to apply the DFT precoding to the OFDM-based waveform on notaccording to the MCS index. For example, it may be possible topreconfigure such that the MCS indices 0 to 4 are indicative of usingthe DFT-S-OFDM (or applying the DFT precoding) and the MCS indices 5 orgreater indicative of using OFDM (or not applying the DFT precoding) inTable 1.

The present invention may also propose a method for the base station totransmit configuration information indicating MCS index-specificwaveforms to the terminals commonly within the cell using a systeminformation block. It may also be possible to propose a method totransmit configuration information indicating whether to applying or notDFT precoding in association with the MCS index to the terminalscommonly within the cell. If the waveform is associated with the MCSindex, the terminal may determine the waveform according to the MCSassigned via the random access response. For example, if the basestation configures to use different waveforms based on the index 6 asthe reference point (or if the base station configures to determinewhether to use DFT precoding or not based on the index 6 as thereference point), the terminal may infer the use of the DFT-S-OFDM(applying the DFT precoding to OFDM-based waveform) for uplinktransmissions from the MCS indices 0 to 6 and the use of the OFDM (usingthe OFDM without applying the DFT precoding) for uplink transmissionfrom the remaining MCS indices.

TABLE 1 Modulation Redundancy MCS Index Order TBS Index Version 0 2 0 01 2 1 0 2 2 2 0 3 2 3 0 4 2 4 0 5 2 5 0 6 2 6 0 7 2 7 0 8 2 8 0 9 2 9 010 2 10 0 11 4 10 0 12 4 11 0 13 4 12 0 14 4 13 0 15 4 14 0 16 4 15 0 174 16 0 18 4 17 0 19 4 18 0 20 4 19 0 21 6 19 0 22 6 20 0 23 6 21 0 24 622 0 25 6 23 0 26 6 24 0 27 6 25 0 28 6 26 0 29 reserved 1 30 2 31 3

As the second approach for the terminal to infer the waveform for use inPUSCH transmission from the resource allocation information, it may beproposed to associate the waveform with the size of allocated frequencyresources. That is, the terminal may determine whether to apply DFTprecoding to uplink PUSCH transmission based on the size of theallocated frequency resources. If the terminal is located at the celledge where SINR is too low to secure coverage for uplink PUSCHtransmission, it is preferred for the terminal to perform the PUSCHtransmission with small frequency resources from the viewpoint ofcoverage. In this case, it may be possible to configure to use OFDM forthe case of being allocated resource blocks (RBs) equal to or greaterthan a specific number (NRB) and DFT-S-OFDM for the case of beingallocated RBs equal to or less than a specific number. Here, theresource block allocation size NRB for use in determining the waveformmay be a value pre-agreed between the terminal and the base station or avalue configured by the base station.

The third and fourth methods according to embodiment 1-1 of the presentinvention are considered only for the case of transmitting a PUSCH inthe initial access procedure. However, in the case where a PUCCHtransmission is required in the initial access procedure, it may also bepossible for the terminal to perform the PUCCH transmission with thesame waveform as the PUSCH transmission waveform that is determinedaccording to the random access response.

The third and fourth methods according to embodiment 1-1 of the presentinvention are directed to the methods for the terminal to infer thewaveform for use in PUSCH transmission from the random access responseor the resource allocation information transmitted by the base station.In the case of determining the waveform based on the random accessresponse, the terminal may interpret other fields of the random accessresponse differently according to the determined waveform as follows.

In the legacy LTE system, the random access response includes a hoppingflag field. This field indicates whether PUSCH frequency hopping isenabled. The DFT-S-OFDM-based LTE uplink transmission is restricted inthat interleaved or comb type subcarrier mapping is not allowed forgenerating a low PAPR signal, which means that it is difficult to obtainfrequency diversity gain. Accordingly, in order to achieve the frequencydiversity gain without compromising the low PAPR signal characteristic,the frequency hopping is used, which is indicated by the random accessresponse being transmitted in the initial access procedure. However,considering that the interleaved or comb type subcarrier mapping schemeis typically more effective than the frequency hopping scheme forachieving frequency diversity gain and that the OFDM imposes norequirements for generating a low PAPR signal, it may be possible toreuse the hopping flag field for indicating whether to use thecontinuous or localized resource allocation or interleaved-type resourceallocation.

That is, if it is determined for the terminal to use the DFT-S-OFDM foruplink transmission according to any of the first to fourth methods, theterminal regards the hopping flag field as a field indicating whether toenable DFT-S-OFDM-based PUSCH hopping. The corresponding field may beset to 0 for disabling the PUSCH frequency hopping and 1 for enablingthe PUSCH frequency hopping. If it is determined for the terminal to usethe OFDM for uplink transmission according to any of the first to fourthembodiments, the terminal may determine whether to perform continuousresource allocation or interleaved-type resource allocation in thefrequency domain based on the hopping flag field.

According to an embodiment of the present invention, if the terminaltransmits a random access preamble and receives a random access responsein the initial access procedure, the terminal may infer a waveformconfiguration method or a waveform to be used for an uplink PUSCHtransmission by the terminal in accordance with the first to fourthmethods. The uplink transmission waveform configuration method may bemaintained until an RRC connection setup is completed by transmitting anuplink signal after receipt of the random access response. If anadditional waveform is not configured for uplink transmission of theterminal even after the RRC connection setup has been completed, theterminal may continue using the uplink waveform used in the initialaccess procedure for uplink transmission. If a separate waveform forPUCCH transmission is configured or whether to apply DFT precoding isnot configured, it may be assumed that the terminal can perform thePUCCH transmission using the same waveform as that for PUSCHtransmission.

Embodiment 1-2

Embodiment 1-2 of the present invention is directed to a method for aterminal to determine a waveform for use in PUSCH and PUCCHtransmissions in the stated of being connected to a base station aftercompleting an RRC connection setup.

The first method is for a base station to configure a waveform for useby the terminal in uplink transmission during an RRC connection setupprocedure. That is, the base station may configure whether to use anOFDM-based waveform or a DFT-S-OFDM-based waveform for PUSCH and PUCCHtransmissions afterward via RRC signaling. The base station may alsoconfigure whether to apply DFT precoding to the OFDM-based waveform forPUSCH and PUCCH transmissions of the terminal via RRC signaling. Beforea specific waveform is newly configured through the above method, theterminal may transmit uplink signals based on the previously configuredwaveform. If whether to apply the DFT precoding is configured, theterminal may transmit uplink signals based on the previously configuredwaveform until a new configuration is received.

The size of the scheduling information for PUSCH resource allocation tothe terminal varies with waveform-specific resource allocationinformation and multiantenna transmission scheme. The terminal mayperform a blind detection on downlink control signal channels to detectscheduling information allocating PUSCH resources to the terminal inconsideration of waveform-specific scheduling information sizes.

The first method has a drawback of not coping promptly with a situationwhere the terminal enters a high-mobility state or the channel conditionvaries quickly because the PUSCH and PUCCH waveform is configured in asemi-static manner. Hereinafter, descriptions are made of the second andthird methods for configuring an uplink waveform via a downlink controlchannel information for uplink scheduling.

The second method is for a base station to transmit schedulinginformation for scheduling uplink transmission of a terminal viadownlink control information (DCI) conveyed by a physical downlinkcontrol channel (PDCCH). Here, the base station may notify the terminalof the waveform to be used via the DCI for scheduling PUSCHtransmission. It may also be possible to notify whether to apply DFTprecoding for PUSCH transmission via DCI. For this purpose, a 1-bitfield for indicating an uplink waveform may be included. The waveformfield may consist of 1 bit and the waveform information field may, byway of example, be set to 0 for indicating use of OFDM and 1 forindicating use of DFT-S-OFDM. A 1-bit field for indicating whether toapply DFT precoding for uplink transmission may also be included.

The third method is for a terminal to infer the waveform to be used fromuplink resource allocation information included in downlink controlchannel instead of adding a field indicating the uplink waveform to thedownlink control channel for uplink scheduling as in the second method.In this case, the base station has to notify the terminal ofsimultaneous use of two waveforms via system information.

As the first approach for the terminal to infer the waveform for use inPUSCH transmission from the resource allocation information, it may beproposed to associate the waveform with the MCS assigned to theterminal. If the terminal is located at a cell edge where the SINR istoo low to secure the coverage, it is preferred to use a low MCS. If theterminal is located around the center of the cell or the cell is small,it is preferred to transmit uplink signals using a high MCS. Theterminal is capable of inferring the waveform to be used from the MCS asresource allocation information included in the random access response.

Table 1 is an MCS table that is used in the LTE system; in the fourthmethod of embodiment 1-2 of the present invention, it is also proposedto preconfigure to use the DFT-S-OFDM or the OFDM according to the MCSindex in the 5G communication system. For example, it may be possible topreconfigure such that the MCS indices 0 to 4 are indicative of usingthe DFT-S-OFDM and the MCS indices 5 or greater are indicative of usingthe OFDM. It may also be possible to propose a method to transmitconfiguration information indicating whether to applying or not DFTprecoding in association with the MCS index to the terminals commonlywithin the cell. For example, if the base station configures to usedifferent waveforms based on the index 6 as the reference point, theterminal may infer the use of the DFT-S-OFDM for uplink transmissionsfrom the MCS indices 0 to 6 and the use of the OFDM for uplinktransmission from the remaining MCS indices.

As the second approach for the terminal to infer the waveform for use inPUSCH transmission from the resource allocation information, it may beproposed to associate the waveform with the size of allocated frequencyresources. If the terminal is located at the cell edge where SINR is toolow to secure coverage for uplink PUSCH transmission, it is preferredfor the terminal to perform the PUSCH transmission with small frequencyresources from the viewpoint of coverage. In this case, it may bepossible to configure to use OFDM for the case of being allocatedresource blocks (RBs) equal to or greater than a specific number (NRB)and DFT-S-OFDM for the case of being allocated RBs equal to or less thana specific number. Here, the resource block allocation size NRB for usein determining the waveform may be a value pre-agreed between theterminal and the base station or a value configured by the base station.

In the second and third methods according to embodiment 1-2 of thepresent invention in which the waveform to be used is determined basedon the downlink control channel information, although the number of bitsrequired in the DCI varies with the waveform, it is necessary to fix thenumber of bits. In the case where the OFDM-based uplink schedulinginformation requires N_(OFDM) bits while the DFT-S-OFDM-based uplinkscheduling information requires N_(DFT-S-OFDM) bits and N_(DFT-S-OFDM)is greater than N_(DFT-S-OFDM), it may be possible to pad the OFDM-baseduplink scheduling information with N_(OFDM)-N_(DFT-S-OFDM) 0s.

The second and fourth methods according to embodiment 1-2 of the presentinvention are directed to the method for the base station to configure awaveform for use in uplink signal transmission of the terminal using thedownlink control channel information for PUSCH scheduling or for theterminal to infer the wave form from the resource allocationinformation. In the case of determining the waveform as above, theterminal may interpret other fields of the downlink control channelinformation differently according to the determined waveform as follows.

In the legacy LTE system, the downlink control information for uplinkscheduling includes a hopping flag field. This field indicates whetherPUSCH frequency hopping is enabled. The DFT-S-OFDM-based LTE uplinktransmission is restricted in that interleaved or comb type subcarriermapping is not allowed for generating a low PAPR signal, which meansthat it is difficult to obtain frequency diversity gain. Accordingly, inorder to achieve the frequency diversity gain without compromising thelow PAPR signal characteristic, the frequency hopping is used, which isindicated by DCI. However, considering that the interleaved or comb typesubcarrier mapping scheme is typically more effective than the frequencyhopping scheme for achieving frequency diversity gain and that the OFDMimposes no requirements for generating a low PAPR signal, it may bepossible to reuse the hopping flag field for indicating whether to usethe continuous or localized resource allocation or interleaved-typeresource allocation.

That is, if it is determined for the terminal to use the DFT-S-OFDM foruplink transmission according to any of the first to fourth methods, theterminal regards the hopping flag field as a field indicating whether toenable DFT-S-OFDM-based PUSCH hopping. The corresponding field may beset to 0 for disabling the PUSCH frequency hopping and 1 for enablingthe PUSCH frequency hopping. If it is determined for the terminal to usethe OFDM for uplink transmission according to any of the first to fourthembodiments, the terminal may determine whether to perform continuousresource allocation or interleaved-type resource allocation in thefrequency domain based on the hopping flag field.

The base station may also include information on the waveform for use bya terminal in transmitting PUCCH carryingacknowledgement/negative-acknowledgement (ACK/NACK) informationcorresponding to PDSCH in the DCI for PDSCH scheduling. In this case,the DCI for PDSCH scheduling may include a field indicating a waveformfor use in PUCCH transmission. This field may be set to 1 to instructthe terminal to use OFDM-based waveform for PUCCH transmission or 0 toinstruct the terminal to use SC-FDMA-based waveform for PUCCHtransmission.

FIGS. 6 and 7 depicts a transmitter of a base station and a receiver ofa terminal for implementing the above embodiments. The transmitter ofthe base station and the receiver of the terminal should operateaccording to the initial access method and apparatus of the 5Gcommunication system proposed in embodiment 1-1 and 1-2.

FIG. 6 is a block diagram illustrating a configuration of thetransmitter of the base station according to an embodiment of thepresent invention.

As shown in FIG. 6 , the transmitter of the base station of the presentinvention includes resource mappers 600, 615, and 630, OFDM modulators605, 620, and 635, and filters 610, 625, and 640. The resource mappers600, 615, and 630 perform QPSK or QAM modulation on data to betransmitted and map the modulated data to time and frequency domainresources. The OFDM modulators 605, 620, and 635 perform OFDM modulationon the resource-mapped signal output from the resource mappers 600, 615,and 630. The OFDM modulation includes performing IFFT and inserting a CPat the beginning of the OFDM symbols. The filters 610, 625, and 640filter the signals output from the OFDM modulators 605, 620, and 635 tomeet frequency band spectrum mask requirements.

The service data are processed by the resource mappers, OFDM modulators,and filters assigned in an service-specific manner to generate physicalchannels and signals. For example, in order to transmit a physicalchannel and signal for an eMBB service, the resource mapper 600, OFDMmodulator 605, and filter 610 assigned for the eMBB transmission operateto generate the physical channel and signal corresponding to the eMBBservice. Here, the resource mapper 600, OFDM modulator 605, and filter610 may generate the physical channel and signal based on a numerologydefined for the eMBB service.

Similarly, common signals including signals for achievingsynchronization and acquiring system information may be processed viathe resource mapper 630, OFDM modulator 635, and filter 640 assigned forthe common signals to generate a physical channel and signalcorresponding to the common signals. Here, the common signals may begenerated based on a numerology defined for the common signals. Theresource mapper 630 may freely configure frequency location fortransmitting the common signals unlike in the legacy LTE system.

The transmitter of the base station includes a multiplexer 645 formultiplexing outputs from the respective filters. The transmitter of thebase station includes a controller 650 for controlling the resourcemappers 600, 615, and 630, and the OFDM modulator 605, 620, and 635, thefilters 610, 625, and 640, and the multiplexer 645 to operateefficiently. Finally, the transmitter of the base station includes an RFunit 655 and an antenna for transmitting the services that are mutuallymultiplexed by the multiplexer 645 to respective terminals.

FIG. 7 is a block diagram illustrating a configuration of the receiverof the terminal according to an embodiment of the present invention. Thereceiver of the terminal includes an antenna, an RF unit 700, filters710 and 740, OFDM demodulators 720 and 750, resource extractors 730 and760, and a controller 770. In order to support services being providedwith two or more different numerologies, multiple filters 710 and 740,OFDM modulators 720 and 750, and resource extractors 730 and 760; FIG. 7depicts an exemplary case of supporting two different services.

In detail, the receiver of the terminal converts a received signal frompassband to baseband by means of the RF unit 700. The converted basebandsignal is input to the filter 710 and 740. It may be possible to turnon/off the filters and change numerologies of the filters depending onthe service subscribed by the terminal. Here, the filters are used toremove interferences caused by the signalsfrequency-division-multiplexed (FDM'ed) in adjacent frequency regions.The OFDM demodulators 720 and 750 are used for performing OFDMmodulation on the filtered signal. The OFDM demodulator 720 and 750 mayeach include a CP remover and an FFT. The resource extractors 730 and760 may extract the physical channels and signals on the resourcesoccupied by the respective services. The controller 770 may control aseries of processes in order for the terminal to operate according tothe above-described embodiments of the present invention.

Although preferred embodiments of the invention have been describedusing specific terms, the specification and drawings are to be regardedin an illustrative rather than a restrictive sense in order to helpunderstand the present invention. It is obvious to those skilled in theart that various modifications and changes can be made thereto withoutdeparting from the broader spirit and scope of the invention. Ifnecessary, the embodiments may be combined in whole or in part. Forexample, embodiments 1-1 and 1-2 of the present invention may becombined in part to form an embodiment for the operations of a basestation and a terminal.

Embodiment 2

Meanwhile, a 5G new radio access technology (NR) is designed to allowfor freely multiplexing various types of services onto time andfrequency resources and assigning waveforms/numerologies and referencesignals dynamically or freely to meet service-specific requirements. Forwireless communications in which great importance is given to thechannel quality and interference measurement for providing terminalswith optimal services, correct channel state measurement is inevitable.Unlike the 4G communication in which the channel and interferencecharacteristics rarely vary with the frequency resources, the 5Gcommunication is characterized in that the channel and interferencecharacteristics significantly vary with services, which makes itnecessary to support subsets of a frequency resource group (FRG) forseparate measurements thereof. Meanwhile, the services being supportedin the NR system are categorized into three categories: enhanced mobilebroadband (eMBB), massive machine type communications (mMTC), andultra-reliable and low-latency communications (URLLC). The eMBB servicesare characterized by high capacity and high mobility communication, themMTC services by low power consumption and massive connections, and theURLLC by ultra-high reliability and low latency. The requirements mayvary with the type of services to be provided to the terminal.

In order for the communication system to provide users with varioustypes of services, there is a need of a method and apparatus formultiplexing different services into the same time period to meet theservice-specific requirements.

The mobile communication system has evolved to a high-speed,high-quality packet data communication system (such as High Speed PacketAccess (HSPA), LTE (or evolved universal terrestrial radio access(E-UTRA)), and LTE-Advanced (LTE-A) defined in the 3^(d) GenerationPartnership Project (3GPP), High Rate Packet Data (HRPD) defined in the3^(rd) Generation Partnership Project-2 (3GPP2), Ultra Mobile Broadband(UMB), and 802.16e defined in the IEEE)) capable of providing data andmultimedia services beyond the early voice-oriented services. Meanwhile,5G or NR standardization is in progress for 5G wireless communicationsystems.

The LTE system as one of the representative broadband wirelesscommunication systems uses orthogonal frequency division multiplexing(OFDM) in the downlink (DL) and single carrier frequency divisionmultiple access (SC-FDMA) in the uplink (UL). The term “uplink” denotesa radio link for transmitting data or control signals from a terminalthat is interchangeably referred to as user equipment (UE) and mobilestation (MS) to a base station (BS) that is interchangeably referred toas evolved node B (eNB), and the term “downlink” denotes a radio linkfor transmitting data or control signals from a base station to aterminal. Such multiple access schemes are characterized by allocatingthe time-frequency resources for transmitting user-specific data andcontrol information without being overlapped with each other, i.e.,maintaining orthogonality, so as to distinguish among user-specific dataand control information.

The LTE system adopts a Hybrid Automatic Repeat Request (HARQ) schemefor physical layer retransmission when decoding failure occurs ininitial data transmission. An HARQ scheme is designed to operate in sucha way that a receiver, when it fails in decoding data, sends atransmitter a negative acknowledgement (NACK) indicative of the decodingfailure in order for the transmitter to retransmit the correspondingdata on the physical layer. The receiver combines the retransmitted datawith the decoding-failed data to improve data reception performance. TheHARQ scheme may also be designed to operate in such a way that thereceiver, when it succeeds in decoding data, sends the transmitter anAcknowledgement (ACK) indicative of successful decoding in order for thetransmitter to transmit new data.

FIG. 8 is a diagram illustrating a basic time-frequency resourcestructure for transmitting downlink data or control channels in an LTEsystem.

In FIG. 1 , the horizontal axis denotes the time, and the vertical axisdenotes the frequency. The smallest transmission unit in the time domainis an OFDM symbol, and N_(symb) OFDM symbols 802 form a slot 806, and 2slots form a subframe 805. Each slot spans 0.5 ms, and each subframespans 1.0 ms. A radio frame 814 is a time unit consisting of 10subframes. In the frequency domain, the smallest transmission unit is asubcarrier, and the total system transmission bandwidth consists ofN_(BW) subcarriers 804.

In the time-frequency resource structure, the basic resource unit is aResource Element (RE) 812 indicated by an OFDM symbol index and asubcarrier index. A Resource Block (RB) (or Physical Resource Block(PRB) 808 is defined by N_(symb) consecutive OFDM symbols 802 in thetime domain and NRB consecutive subcarriers 810 in the frequency domain.That is, one RB 808 consists of N_(symb)×N_(RB) REs 812. Typically, theRB is the smallest data transmission unit. In the LTE system,N_(symb)=7, N_(RB)=12, and N_(BW) is proportional to the systemtransmission bandwidth; a non-LTE system may use different values. Thedata rate increases in proportion to the number of RBs scheduled to theterminal.

For the LTE system, 6 transmission bandwidths are defined. In the caseof an FDD system in which downlink and uplink are separated infrequency, the downlink transmission bandwidth and uplink transmissionbandwidth may differ from each other. The channel bandwidth denotes anRF bandwidth in comparison with the system transmission bandwidth. Table2 shows the relationship between the system transmission bandwidth andchannel bandwidth defined in the LTE system. For example, an LTE systemhaving a 10 MHz channel bandwidth uses the transmission bandwidth of 50RBs.

TABLE 2 Channel bandwidth 1.4 3 5 10 15 20 BW_(Channel) [MHz]Transmission bandwidth 6 15 25 50 75 100 configuration N_(RB)

The downlink control information is transmitted in N OFDM symbols at thebeginning of the subframe. Typically, N={1, 2, 3}. Accordingly, N valuevaries, at every subframe, with the control information amount to betransmitted. The control information includes a control channeltransmission period indicator for indicating a number of OFDM symbolsfor conveying the control information, scheduling information fordownlink or uplink data transmission, and an HARQ ACK/NACK signal.

In the LTE system, the downlink or uplink data scheduling information istransmitted from the base station to the terminal using Downlink ControlInformation (DCI). The DCI is categorized into different DCI formatsdepending on the purpose, e.g., indicating UL grant for UL datascheduling or DL grant for DL data scheduling, indicating usage forcontrol information that is small in size, indicating whether multipleantenna-based spatial multiplexing is applied, and indicating usage forpower control. For example, the DCI format 1 for DL grant is configuredto include at least the following information.

-   -   Resource allocation type 0/1 flag: Resource allocation type 0/1        flag indicates whether the resource allocation scheme is Type 0        or Type 1. A Type-0 is to allocate resources in units of        Resource Block Group (RBG) by applying a bitmap scheme. In the        LTE system, the basic unit of scheduling may be a Resource Block        (RB) that is expressed by time-frequency domain resources, and        the RBG may include multiple RBs and may be the basic unit of        scheduling in the Type-0 scheme. A Type-1 is to allocate a        particular RB in an RBG.    -   Resource block assignment: Resource block assignment indicates        an RB allocated for data transmission. The resources may be        determined depending on the system bandwidth and the resource        allocation scheme.    -   Modulation and coding scheme (MCS): MCS indicates a modulation        scheme used for data transmission and a size of a transport        block to be transmitted.    -   HARQ process number: HARQ process number indicates a process        number of HARQ.    -   New data indicator: New data indicator indicates whether the        HARQ transmission is an initial transmission or a        retransmission.    -   Redundancy version: Redundancy version indicates a redundancy        version of HARQ.    -   TPC command for PUCCH: Transmit Power Control (TPC) command for        Physical Uplink Control Channel (PUCCH) indicates a power        control command for a PUCCH that is an uplink control channel.

The DCI may be transmitted over a Physical Downlink Control Channel(PDCCH) or Enhanced PDCCH (EPDCCH) after undergoing a channel coding andmodulation process. In the following description, the phrase PDCCH orEPDCCH transmission/reception may be interchangeably used with DCItransmission/reception.

Typically, the DCI may undergo channel coding for each terminalindependently, and then the channel-coded DCI may be configured with itsdependent PDCCH and transmitted. In the time domain, a PDCCH may bemapped and transmitted during the control channel transmission period.The frequency-domain mapping location of the PDCCH may be determined byan ID of each terminal, and it may be spread throughout the entiresystem transmission band.

Downlink data may be transmitted over a Physical Downlink Shared Channel(PDSCH) that is a physical channel for downlink data transmission. APDSCH may be transmitted after the control channel transmission period,and the scheduling information such as the detailed mapping location inthe frequency domain and the modulation scheme may be indicated by theDCI that is transmitted over the PDCCH.

Using MCS as part of the control information constituting the DCI, thebase station notifies the terminal of the modulation scheme applied tothe PDSCH to be transmitted and the size of data (e.g., Transport BlockSize (TBS)) to be transmitted. In an embodiment, the MCS has a bitwidthof 5 or less or greater than 5. The TBS corresponds to the size givenbefore channel coding for error correction is applied to the data (e.g.,Transport Block (TB)) to be transmitted by the base station.

The modulation schemes supported by the LTE system may includeQuadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation(QAM), and 64QAM, and they have modulation orders (Q_(m)) 2, 4, and 6,respectively. That is, the QPSK modulation transmits 2 bits per symbol,the 16QAM transmits 4 bits per symbol, and the 64QAM transmits 6 bitsper symbol. It may also be possible to use 256QAM or higher ordermodulation depending on the system.

FIG. 9 is a diagram illustrating a basic time-frequency resourcestructure for transmitting uplink data or control channels in an LTE-Asystem.

In FIG. 9 , the horizontal axis denotes the time, and the vertical axisdenotes the frequency. The smallest transmission unit in the time domainis an SC-FDMA symbol, and N_(symb) SC-FDMA symbols 902 form a slot 906.Two slots form a subframe 905. The smallest transmission unit in thefrequency domain is a subcarrier, and the total system transmissionbandwidth consists of N_(BW) subcarriers 904. N_(BW) may be proportionalwith the system transmission bandwidth.

In the time-frequency domain, the basic resource unit is RE 912, andeach RE is defined by one SC-FDMA symbol index and one subcarrier index.A resource block (RB) 908 is defined by N_(symb) consecutive SC-FDMAsymbols in the time domain and NRB consecutive subcarriers in thefrequency domain. Accordingly, one RB consists of N_(symb)×N_(RB) REs.Typically, the smallest data or control information transmission unit isRB. A physical uplink control channel (PUCCH) is mapped to a frequencyregion corresponding to one RB and transmitted during a time period ofone subframe.

The LTE standard defines a relationship between the PDSCH or thePDCCH/EPDCCH carrying a semi-persistent scheduling (SPS) release and thePUCCH or physical uplink shared channel (PUSCH) carrying the HARQACK/NACK corresponding to the PDSCH, PDCCH, or EPDCCH. For example, inan LTE system operating in the FDD mode, the HARQ ACK/NACK correspondingto the PDSCH or the PDCCH or EPDCCH carrying the SPS release, the PDSCHor the PDCCH or EPDCCH being transmitted at the (n−4)^(th) subframe, iscarried in the PUCCH or PUSCH being transmitted at the n^(th) subframe.

The LTE system employs an asynchronous HARQ scheme for DL HARQ. That is,if an eNB receives an HARQ NACK for initially transmitted data from aUE, it may freely determine a retransmission timing through a schedulingoperation. If the UE fails to decode the received data, it stores theerroneous initial data and combines the buffered data with theretransmitted data.

If the UE receives a PDSCH carrying the DL data transmitted by the eNBat the n^(th) subframe, it transmits UL control information includingthe HARQ ACK/NACK corresponding to the DL data to the eNB through thePUCCH or PUSCH at the (n+k)^(th) subframe. Here, k is determineddifferently depending on the duplex mode (i.e., FDD or time divisionduplex (TDD)) and subframe configuration in use by the LTE system. Forexample, k is fixed to 4 in the FDD LTE system. Meanwhile, k may varyaccording to the subframe configuration and subframe index in the TDDLTE system.

The LTE system employs a synchronous HARQ scheme with a fixed datatransmission timing for UL transmission distinct from the DL HARQ. Thatis, the UL-DL timing relationship between the PUSCH and PDCCH that isfollowed by the PUSCH and a physical hybrid indicator channel (PHICH)carrying the DL HARQ ACK/NACK corresponding to the PUSCH is fixedaccording to a rule as follows.

If the UE receives a PDCCH carrying UL scheduling control information ora PHICH carrying a DL HARQ ACK/NACK from the eNB at the n^(th) subframe,it transmits UL data through a PUSCH at the (n+k)^(h) subframe based onthe control information. Here, k is determined differently depending onthe duplex mode in use, i.e., FDD or TDD, and its configuration. Forexample, k is fixed to 4 in the FDD LTE system. Meanwhile, k may varyaccording to the subframe configuration and subframe index in the TDDLTE system.

In the FDD LTE system, the eNB transmits a UL grant or a DL controlsignal and data to the UE at the n^(th) subframe, the UE receives the ULgrant or the DL control signal and data at the n^(th) subframe. If theUE receives a UL grant at the n^(th) subframe, it transmits uplink dataat the (n+4)^(th) subframe. If the UE receives a DL control signal anddata at the n^(th) subframe, it transmits an HARQ ACK/NACK correspondingto the DL data at the (n+4)^(th) subframe. In this case, a time periodgiven for the UE to prepare UL data transmission scheduled via the ULgrant or transmission of HARQ ACK/NACK corresponding to the DL databecomes 3 ms, which is equal to the duration of three subframes.

The UE receives the PHICH carrying the DL HARQ ACK/NACK from the eNB atthe i^(th) subframe and the DL HARQ ACK/NACK corresponding to the PUSCHtransmitted by the UE at the (i+k)^(th) subframe. Here, k is determineddifferently depending of the duplex mode (i.e., FDD or TDD) and itsconfiguration in use by the LTE system. For example, k is fixed to 4 inthe FDD LTE system. Meanwhile, k may vary according to the subframeconfiguration and subframe index in the TDD LTE system.

FIGS. 10 and 11 are diagrams illustrating frequency-time resourcesallocated for transmitting data of eMBB, URLLC, and mMTC services beingconsidered in the 5G or NR system.

FIGS. 10 and 11 show how the frequency and time resources are allocatedfor information transmission in a system. In FIG. 10 , the eMBB, URLLC,and mMTC data are allocated across the entire system frequency band1000. If the URLLC data 1030, 1050, and 1070 are generated to betransmitted during the transmission of the eMBB 1010 and mMTC 1090 inspecific frequency bands, parts of the eMBB 1010 and mMTC 1090 may bepunctured such that the URLLC data 1030, 1050, and 1070 are inserted.Because the URLLC services are delay-sensitive among the aforementionedservices, the URLLC data 1030, 1050, and 1070 may occupy parts of theresources allocated for eMBB data 1010. In the case of transmitting theURLLC data on the resources allocated for the eMBB data, the eMBB datamay not transmitted on the overlapping frequency-time resources, whichmay degrade eMBB data transmission throughput. That is, in the abovecase, the resource allocation for the URLLC data transmission may causeeMBB data transmission failure.

In FIG. 11 , the system frequency band 1100 is divided into sub-bands1110, 1120, and 1130 for data transmissions of different services. Thesub-band configuration information may be preconfigured and transmittedfrom a base station to a terminal by higher layer signaling. And thesub-band-related information provide the services without anyarbitrarily separate transmission of sub-band configuration informationto the terminal by base stations or network nodes. In FIG. 11 , thesub-bands 1110, 1120, and 1130 are allocated for eMBB data transmission,URLLC data transmission, and mMTC data transmission, respectively.

Throughout the embodiment, the transmission time interval (TTI) forURLLC transmission may be shorter that the TTI for eMBB or mMTCtransmission. The acknowledgement corresponding to the URLLC data may betransmitted more quickly than the acknowledgement corresponding to theeMBB or mMTC data, resulting in low latency informationtransmission/reception.

FIG. 12 is a diagram illustrating a procedure for segmenting a transportblock into multiple code blocks and attaching a CRC to the code blocks.

In reference to FIG. 12 , a CRC 1202 may be attached at the beginning orend of a transport block (TB) 1200 to be transmitted in uplink ordownlink. The CRC may have a fixed length of 16 bits or 24 bits or avariable length varying with channel condition and may be used fordetermining whether the channel coding is successful. A block includingthe TB 1200 and the CRC 1202 may be segmented into multiple code blocks(CBs) 1220, 1222, 1224, and 1226 as denoted by reference number 1210.Each CB has a predetermined maximum size as far as possible and, in thiscase, the last CB 1226 may be smaller in size than the other codeblocks; it may be possible to add 0s, random values, or is to the lastCB to make the last CB to be equal in length to other CBs.

It may be possible to add CRCs 1240, 1242, 1244, and 1246 to therespective CBs. The CRC may have a fixed length of 16 bits, 24 bits, orthe like and may be used for determining whether the channel coding issuccessful. However, attaching the CRC 1202 to the TB and attaching theCRCs 1240, 1242, 1244, and 1246 to the respective CBs may be omitteddepending on the type of the channel code to be applied to the CBs. Forexample, in the case of applying an LDPC code rather than a turbo code,attaching the CRCs 1240, 1242, 1244, and 1246 to the respective CBs maybe omitted. However, even if the LDPC code is applied, the CRCs 1240,1242, 1244, and 1246 may be attached to the CBs. Even in the case ofusing a polar code, it may be possible to omit attaching any CRC.

FIG. 13 is a diagram illustrating an outer code-based transmissionmethod, and FIG. 14 is a diagram illustrating a structure of an outercode-based communication system.

A description is made of the method for transmitting a signal with anouter coded with reference to FIGS. 13 and 14 .

In FIG. 13 , a TB is segmented into multiple CBs of which bits orsymbols 1310 located at identical bit-positions are encoded with asecond channel code to generate parity bits or symbols 1320 as denotedby reference number 1300. Next, CRCs 1330 and 1340 may be respectivelyattached to the CBs and parity CBs generated by encoding with the secondchannel code. It may be possible to attach the CRC or not depending onthe type of the channel code. For example, if a turbo code is used as afirst channel code, the CRCs 1330 and 1340 are attached and then the CBsand parity CBs may be encoded with the first channel code.

The TB is delivered from a higher layer to a physical layer. Thephysical layer regards the TB as data. A CRC is attached to the TB. TheCRC may be generated with the TB and a cyclic generator polynomial,which may be defined in various manners. For example, assuming that thecyclic generator polynomial isg_(CRC24A)(D)=D24+D23+D18+D17+D14+D11+D10+D7+D6+D5+D4+D3+D+1 for a24-bit CRC, if L=24, it may be possible to determinea₀D^(A+23)+a₁D^(A+22)+ . . . +a_(A−1)D²⁴+p₀D²³+p₁D²²+ . . . +p₂₂D¹+p₂₃divisible by g_(CRC24A)(D) with the remainder 0 as CRCs CRC p₀, p₁, p₂,p₃, . . . , p_(L−1). Although the description has been made to the casewhere the CRC length L is 24, L may be set to 12, 16, 24, 32, 40, 48,64, or the like. A CRC is attached to the CBs and, in this case, the CRCmay be generated with a cyclic generator polynomial different from thatused in generating the CRC attached to the TB.

In the legacy LTE system, if an initial transmission fails,retransmission is performed in unit of TB. Unlike in the legacy LTEsystem, it may be considered to perform the retransmission by CB ratherthan TB. In order to accomplish this, it may be necessary for theterminal to transmit multi-bit HARQ-ACK feedback per TB. The basestation may also provide information indicating parts to beretransmitted in the control information for scheduling theretransmission.

In reference to FIG. 14 , in the case of using the outer code, the datato be transmitted passes the second channel coding encoder 1430.Examples of the channel coded for the second channel coding may includea Reed-Solomon code, a BCH code, a Raptor code, and a parity bitgeneration code. The bits or symbols that pass the second channel codingencoder 1430 pass a first channel coding encoder 1440. Examples of thechannel code for the first channel coding may include a Convolutionalcode, an LDPC code, a Turbo code, and a Polar code. If the channel-codedsymbols are received by a receiver over a channel 1450, the receiver mayprocess the received signals by means of a first channel coding decoder1460 and a second channel coding decoder 1470 in serial order. The firstand second channel coding decoders 1460 and 1470 may perform oppositeoperations of the first and second coding encoders 1440 and 1430,respectively.

In the case of not using the outer code, only the first channel codingencoder 1400 and the first channel coding decoder 1420 are used in thechannel coding block diagram with no second channel coding encoder anddecoder. Even in the case of not using the outer code, the first channelcoding decoder 1420 may have an identical configuration with that of thefirst channel coder 1440 for the case of using the outer coder.

In the following description, an eMBB service is referred to as firsttype service, and eMBB service data are referred to as first type data.The terms “first type service” and “first type data” are not limited toeMBB, and they may include other service types requiring a high speeddata transmission or broadband transmission. Meanwhile, a URLLC serviceis referred to as second type service, and URLLC service data arereferred to as second type data. The terms “second type service” and“second type data” are not limited to URLLC, and they may include otherservice types requiring low latency, high reliability transmission, orlow latency and high reliability transmission. Meanwhile, an mMTCservice is referred to as third type service, and mMTC service data arereferred to as third type data. The terms “third type service” and“third type data” are not limited to mMTC, and they may include otherservice types requiring low speed, broad coverage, or low powertransmission. In an embodiment, the first type service may be understoodas including or not including the third type service.

The physical layer channel structures for transmitting the three typesof services or data may differ from each other. For example, they maydiffer in at least one of TTI length, frequency resource allocationunit, control channel structure, and data mapping scheme.

Although three types of services and three types of data are enumeratedabove, the principle of the present invention can be applied to thecases were a larger number of service and data types exist.

In an embodiment, the terms “physical channel” and “signal” in use forLTE and LTE-A systems are used for explaining the proposed method anddevice. However, the principle of the present invention is applicable toother wireless communication systems as well as the LTE and LTE-Asystems.

As described above, the present invention defines communicationoperations between a terminal and a base station for transmitting thefirst, second, and third type services or data and proposes a method forserving the terminals in such a way of scheduling the different types ofservices or data for the respective terminals in the same system. In thepresent invention, the terms “first type terminal”, “second typeterminal”, and “third type terminal” are intended to indicate theterminals for which the first, second, and third types of services ordata, respectively, are scheduled. In an embodiment, the first typeterminal, second type terminal, and third type terminal may be identicalwith or different from each other.

Exemplary embodiments of the present invention are described in detailwith reference to the accompanying drawings. Detailed descriptions ofwell-known functions and structures incorporated herein may be omittedto avoid obscuring the subject matter of the present invention. Further,the following terms are defined in consideration of the functionality inthe present invention, and they may vary according to the intention of auser or an operator, usage, etc. Therefore, the definition should bemade on the basis of the overall content of the present specification.

In the following description, the term “base station (BS)” denotes anentity for allocating resources to terminals and is intended to includeat least one of a Node B, an evolved Node B (eNB), a radio access unit,a base station controller, and a network node. The term “terminal” isintended to include a user equipment (UE), a mobile station (MS), acellular phone, a smartphone, a computer, and a multimedia system with acommunication function. Although the description is directed to an LTEor LTE-A system by way of example, the present invention is applicableto other communication systems having a similar technical background andchannel format. For example, the present invention is applicable to the5G mobile communication technology (5G new radio (NR)) under developmentafter LTE-A. It will be understood by those skilled in the art that thepresent invention can be applied even to other communication systemswith a slight modification without departing from the spirit and scopeof the present invention.

In the present invention, the TTI denotes a unit of time fortransmitting control and data signals or only the data signal. In thelegacy LTE system, by way of example, the TTI is equal in length to onesubframe as a unit of time, i.e., 1 ms, in downlink. In the presentinvention, the TTI may denote a unit of time for transmitting a controland data signal or only the data signal in uplink. In the legacy LTEsystem, the TTI is a time unit of 1 ms equal in length to one subframein both downlink and uplink.

Meanwhile, one of the important criteria determining the throughput of awireless cellular communication system is packet data latency. LTEemploys a TTI of 1 ms, which is identical with the length of onesubframe. An LTE system employing a TTI of 1 ms may support a UEoperating with a TTI shorter than 1 ms (short-TTI UE). Meanwhile, the 5GNR may employ a TTI shorter than 1 ms. The short-TTI UE is suitable forlatency-sensitive services such as voice over LTE (VoLTE) and remotecontrol services and is expected to be a means for realizingmission-critical IoT. It may also be expected that the short-TTI UE canbe a means for realizing cellular-based mission-critical IoT.

In the present invention, the terms “physical channel” and “signal” inuse for the LTE or LTE-A system may be interchangeably used with theterms “data” or “control signal”. For example, although PDSCH is aphysical channel carrying normal-TTI data, it may be referred to asnormal-TTI data in the present invention.

Unless the TDD system is specified, the description is made under theassumption of the FDD system. However, the method and apparatus proposedin the present invention for use in the FDD system is applicable to theTTD system with slight modifications.

In the present invention, the term “higher layer signaling” denotes asignaling method for the base station to transmit a signal to the UE ona downlink data channel of the physical layer or for the UE to transmita signal to the base station on an uplink data channel of the physicallayer and may be referred to as RRC signaling or MAC control element(CE) signaling.

In the following description, the term “transmit end” may be used toindicate a base station in downlink and terminal in uplink. The term“receive end” may be used to indicate the terminal in downlink and thebase station in uplink.

In the following description, the term “sub-TB” may be understood as avirtual concept indicating a bundle of one or more CBs.

Embodiment 2-1

Embodiment 2-1 is directed to a method for a terminal to report amaximum CB size to a base station.

After connecting to the base station, the terminal reports to the basestation the maximum CB size that the terminal supports in transmittingdata. The report may mean transmitting UE capability including themaximum CB size supported by the terminal (UE).

Embodiment 2-2

Embodiment 2-2 is directed to a method for configuring a maximum CB sizefor use in uplink or downlink data transmission to a terminal, which isdescribed with reference to FIG. 15 .

The base station transmits to the terminal the information on themaximum CB size for use in data transmission via higher layer signaling.Before receiving the maximum CB size information, the terminal mayassume a value pre-agreed between the terminal and the base station asthe maximum CB size. Once the maximum CB size information is received,the terminal may assume a value indicated by the maximum CB sizeinformation as the maximum CB size for use in data communication. Themaximum CB size information may include a value for use in segmenting aTB into one or more CBs.

FIG. 15 is a flowchart illustrating a procedure for data communicationusing a maximum CB size between a base station and a terminal. The basestation configure the maximum CB size to the terminal via higher layersignaling at step 1500. Although the description is made of the casewhere the maximum CB size information is transmitted from the basestation to the terminal via higher layer signaling, the maximum CB sizeinformation may be transmitted, at step 1500, via DCI as a downlinkcontrol signal, a system information block (SIB), or a combination ofthe higher layer signaling and the DCI. In this embodiment, the maximumCB size may vary between uplink and downlink data transmissions.

At step 1510, the base station and the terminal may perform datacommunication using the configured maximum CB length. If a maximum CBlength is used for data communication, this may mean that thetransmitter segments a TB into one or more CBs based on the maximum CBlength and that the receiver performs channel decoding with the CBlength calculated based on the maximum CB length. The receiver maycalculate a number of CBs and the length of each CB based on the maximumCB length upon receipt of one TB, perform channel decoding on the CBswith the calculated length, and perform, if a CRC exists at apredetermined position, a CRC test to determine whether the transmissionis successful.

Embodiment 2-2-1

Embodiment 2-2-1 explains a method for a base station and an terminal tosegmenting a TB into one or more CBs using a configured maximum size andadding a CRC in embodiment 2-2. Embodiment 2-2-1 is an example ofembodiment 2, which may include various alternative examples.

In this embodiment, Z denotes a maximum CB size possible for one CB, andB denotes a size of a TB. In this embodiment, L_(CB) denotes a length ofa CRC being attached to a CB, and L_(TB) denotes a length of a CRC beingattached to a TB. In this embodiment, C denotes the number of CBs.

In this embodiment, the maximum CB size, denoted by Z, may be a valuethat the base station configures to the terminal. In this embodiment,N_(CB) may be a value greater than 0, which is pre-agreed between thetransmitter and the receiver, and indicate the CRC length of the CB. Inthe following description, ┌X┐ denotes an integer greater than X and └X┘denotes the greatest integer less than X.

The total number of CBs, denoted by C, may be determined as follows.

if B ≤ Z,  L_(CB) = 0  Number of code blocks: C=l  B′ = B else  L_(CB) =N_(CB)  ${{Number}{of}{code}{blocks}:C} = \left\lceil \frac{B}{Z - L_{CD}} \right\rceil$ B′ = B+C·L_(CB) end if

In the above description, the CRC length per CB and the number of CBsare determined based on the configured maxim CB size Z and, as aconsequence, the total number of bits of data to be transmitted isdetermined. Hereinafter, how to segment a TB into CBs is described. Inthe following description, cd denotes the k^(th) bit of the r^(th) CB.

The number of bits for each CB is calculated as follows.

First segment size: K₊ is the smallest value included in a specific setamong K values satisfying B′≤C·K (the specific set may be a setincluding values pre-agreed between the transmitter and the receiver).if C=l number of CBs with size K₊: C₊=1, K⁻=0, C⁻=0 else if C>1 Secondsegment size: K⁻ is the largest value included in a specific set among Kvalues satisfying K<K₊ (the specific set may be a set including valuespre-agreed between the transmitter and the receiver). Δ_(K) = K₊ − K⁻${{number}{of}{CBs}{with}{size}K_{-}:C} - \left\lfloor \begin{matrix}{{C \cdot K_{+}} - B^{\prime}} \\\Delta_{k}\end{matrix} \right\rfloor$ number of CBs with size K_(+:) C+ = C − C⁻end if number of 0 NULL padding bits: F = C₊ ·K₊ + C⁻ · K⁻ − B′ for k =0 to F-1   C_(0k) =<NULL> end for k = F s = 0 for r = 0 to C-1  if r <C⁻   K_(r) = K⁻  else   K_(r) = K₊  end if  perform [STEP 1] below endfor [STEP 1 start] while k < K_(r) − L_(CB)  C_(rk) = b_(s)  k = k+l  s= s+1 end while if C > 1 calculate L_(CB)-bit CRC. Filler bit isregarded as 0.  while k < K_(r)   C 

 ··· P 

; prk denote bits of CRC   k = k+l  end while end if k = 0 [STEP 1 end]

indicates data missing or illegible when filed

Although the zero or NULL padding bits are inserted at the beginning byway of example in the above embodiment, and it may be possible to insertthe padding bits in the middle or at the end. It may also be possible toarrange the filler bits at the beginning or end of every CB in adistributed manner as shown in FIGS. 18 and 19 .

FIG. 16 is a flowchart illustrating an operation of a transmitteraccording to an embodiment of the present invention. The transmitter mayconfigure a maximum CB size to a terminal at step 1600, segment a TBinto one or more CBs based on the preconfigured maximum CB size Z andadds an CRC to the CB at step 1610.

FIG. 17 is a flowchart illustrating an operation of a receiver accordingto an embodiment of the present invention. The receiver, e.g., aterminal, may configure itself, at step 1700, with a maximum CB sizereceived from a base station, discern one or more CBs based on thepreconfigured maximum CB size Z at step 1710, and perform a CRC testafter decoding the CB to determine whether the decoding is successful atstep 1720.

Embodiment 2-2

Embodiment 2-2 is directed to a method for segmenting a TB into one ormore CBs based on a maximum CB size configured between a base stationand a terminal and attaching a CRC to the CBs. Embodiment 2-2 is anexample of embodiment 2, which may include various alternative examples.

In this embodiment, a maximum value K_(max) and a minimum value K_(min)of a CB length may be pre-agreed between the base station and theterminal. In this embodiment, B denotes a size of a TB. In thisembodiment, L_(CB) denotes a length of a CRC being attached to a CB, andL_(TB) denotes a length of a CRC being attached to a TB. In thisembodiment, C denotes a number of CBs. In this embodiment, the basestation may configure the maximum CB size K_(max) and the minimum CBsize to the terminal. In this embodiment, N_(CB) may be a value greaterthan 0, which is pre-agreed between the transmitter and the receiver,and indicates the CRC length of the CB. In this embodiment, ┌X┐ denotesan integer greater than X and └X┘ denotes the greatest integer less thanX. In this embodiment, K_(r) denotes the length of the r^(th) CB.

if B≤K_(max),  L_(CB) = 0  Number of code blocks: C=l  B′ = B else L_(CB) = N_(CB)  ${{Number}{of}{code}{blocks}:C} = \left\lceil \frac{B}{K_{\max} - L_{CB}} \right\rceil$ B′ = B+C·L_(CB) end if if C=1,  CB size K₀ = ┌B′lKmin┐ · K_(min) number of Filler bits F₀ = K′ · C − B else  temporary length of CB J=┌B′/C┐ Temporary length of CB K′= ┌J/K_(min)┐ · K_(min)  Number ofFiller bits F₀ = K₀ − B  γ = F′modC  for r = 0 to C-1   if r ≤ C − γ-1     filler bit of r^(th) CB F_(r) = [F/C]     CB length of r^(th) CBK_(r) = [B′/C] + F,   else      filler bit of r^(th) CB F_(r) = ┌F/C┐     CB length of r^(th) CB K_(r) = |B′C| + F,   end if  end for r endif s = 0 for r = 0 to C-1  for k = 0 to K_(r) − F_(r) − 1   C_(rk) = bs  s = s+1  end for k  for k = K_(r) − F_(r) − 1 to K_(r) − 1   c_(rk)=<NULL>   s = s+1  end for k end for

Although the description is directed to the exemplary case where no CRCis attached to the CB, it may be possible to modify, if a number of CBsis greater than 1, such that a CRC is attached every CB.

Embodiment 2-3

Embodiment 2-3 is directed to a method for a base station to determine amaximum CB size according to a type of data to be transmitted in orderfor a terminal to transmit/receive a signal based on the maximum CBsize.

The type of data may be categorized based on the information containedin a control signal for scheduling the terminal. The informationcontained in the control signal may be delivered with predetermined bitsor a specific RNTI value masked into a CRC attached to a downlinkcontrol signal (DCI). The RNTI value may indicate the type of the databeing transmitted by the base station. For example, the specific RNTIvalue may be indicative of system information RNTI (SI-RNTI) orterminal-specific data (C-RNTI). For example, the maximum CB size may beset to 6144 for data transmission corresponding to the control signal towhich the SI-RNTI is applied and 12288 for data transmissioncorresponding to the control signal to which the C-RNTI is applied.Alternatively, the maximum CB size may be set to 6144 for simultaneousdata transmission to more one terminal and 12288 for data transmissionto a specific terminal.

Embodiment 2-4

Embodiment 2-4 is directed to a method for determining the maximum CBsize based on a TBS in use for data transmission between a base stationand a terminal.

The base station and the terminal may pre-agree thresholds such as afirst TBS threshold, a second TBS threshold, . . . , M*° TBS threshold.It may be possible to determine the maximum CB size by comparing the TBSin use for actual data transmission with the TBS thresholds. Forexample, the maximum CB size may be set to 6144 for the TBS less thanthe first TBS threshold and 12288 for the TBS greater than the first TBSthreshold.

Embodiment 2-5

Embodiment 2-5 is directed to a method for determining the maximum CBsize based on an MCS value in use for data transmission between a basestation and a terminal.

The base station and the terminal may pre-agree thresholds such as afirst MCS threshold, a second MCS threshold, . . . , M^(th) MCSthreshold. It may be possible to determine the maximum CB size bycomparing the MCS in use for actual data transmission with the MCSthresholds. For example, the maximum CB size may be set to 6144 for datatransmission with an MCS less than the first MCS threshold and 12288 fordata transmission with an MCS greater than the first MCS threshold.

The terminal and the base station composed, each, of a transmitter, areceiver, and a processor for implementing the methods of the aboveembodiments are depicted in FIGS. 20 and 21 , respectively. In order toimplement the method for determining a maximum CB size for use in datacommunication between the base station and the terminal as described inembodiments 2-1 to 2-5, the transmitter, receiver, and processor of eachof the base station and the UE should operate as described in therespective embodiments.

FIG. 20 is a block diagram illustrating a configuration of a terminalaccording to an embodiment of the present invention. As shown in FIG. 20, the terminal may include a processor 2010, a receiver 2000, and atransmitter 2020. According to an embodiment of the present invention,the receiver 2000 and the transmitter 2020 may be collectively referredto as a transceiver. The transceiver may transmit and receive signals toand from a base station. The signals may include control information anddata. The transceiver may include a radio frequency (RF) transmitter forfrequency-up-converting and amplifying a signal to be transmitted and anRF receiver for low-noise-amplifying and frequency-down-converting areceived signal. The transceiver may output the signal received over aradio channel to the processor 2010 and transmit the signal output fromthe processor 2010 over the radio channel.

According to an embodiment of the present invention, the processor 2010may control overall operations of the UE. For example, the processor2010 may control the receiver 2000 to receive a downlink data signalfrom a base station and perform CB decoding based on a preconfigured orpredetermined maximum CB size. Afterward, the transmitter 2020 maytransmit HARQ-ACK feedback information containing decoding result.

FIG. 21 is a block diagram illustrating a configuration of a basestation according to an embodiment of the present invention. As shown inFIG. 21 , the base station may include a processor 2110, a receiver2100, and a transmitter 2120. According to an embodiment of the presentinvention, the receiver 2100 and the transmitter 2120 may becollectively referred to as a transceiver. The transceiver may transmitand receive signals to and from a terminal. The signals may includecontrol information and data. The transceiver may include an RFtransmitter for frequency-up-converting and amplifying a signal to betransmitted and an RF receiver for low-noise-amplifying andfrequency-down-converting a received signal. The transceiver may outputthe signal received over a radio channel to the processor 2110 andtransmit the signal output from the processor 2110 over the radiochannel.

According to an embodiment of the present invention, the processor 2110may control overall operations of the base station. For example, theprocessor 2110 may determine a maximum CB size and control to generateand transmit corresponding configuration information. Afterward, thetransmitter 2020 generates CBs based on the maximum CB size andtransmits CRC-attached CBs, and the receiver 2100 receives HARQ-ACKinformation from the terminal.

According to an embodiment of the present invention, the processor 2110may control to generate downlink control information (DCI) or a higherlayer signaling signal including the number of maximum CB size. In thiscase, the DCI or higher layer signaling signal may include informationindicating whether the maximum CB size information on the scheduledsignal is included therein.

The embodiments disclosed in the specification and drawings are proposedto help explain and understand the present invention rather than tolimit the scope of the present invention. It is obvious to those skilledin the art that modifications and changes can be made thereto withoutdeparting from the spirit and scope of the present invention. Ifnecessary, the embodiments may be combined in whole or in part. Forexample, the base station and the terminal may operate according to acombination of parts of embodiments 2-1, 2-2-1, and 2-4 of the presentinvention. Although the embodiments been directed to the FDD LTE system,the present invention can include alternative embodiments directed toother systems such as TDD LTE and 5G NR systems without departing fromthe technical sprit of the present invention.

What is claimed:
 1. A method performed by a terminal in a wirelesscommunication system, the method comprising: determining a maximum codeblock size based on a transport block size and modulation and codingscheme (MCS) information; determining a number of code blocks for thetransport block; and segmenting the transport block into the determinednumber of code blocks.
 2. The method of claim 1, wherein the number ofcode blocks for the transport block is determined based on a firstvalue, the maximum code block size, and a code block cyclic redundancycheck (CRC) size, and wherein the first value is a sum of the transportblock size and a transport block CRC size.
 3. The method of claim 1,wherein in case that a sum of the transport block size and a transportblock cyclic redundancy check (CRC) size is less than or equal to themaximum code block size, the number of code blocks for the transportblock is determined as
 1. 4. The method of claim 1, wherein in case thata sum of the transport block size and a transport block cyclicredundancy check (CRC) size is greater than the maximum code block size,the number of code blocks for the transport block is determined bydividing a first value by a second value, and wherein the first value isa sum of the transport block size and the transport block CRC size andthe second value is obtained by subtracting a code block CRC size fromthe maximum code block size.
 5. The method of claim 1, furthercomprising performing low density parity check coding (LDPC) for thecode blocks.
 6. A method performed by a base station in a wirelesscommunication system, the method comprising: determining a maximum codeblock size based on a transport block size and modulation and codingscheme (MCS) information; determining a number of code blocks for thetransport block; and segmenting the transport block into the determinednumber of code blocks.
 7. The method of claim 6, wherein the number ofcode blocks for the transport block is determined based on a firstvalue, the maximum code block size, and a code block cyclic redundancycheck (CRC) size, and wherein the first value is a sum of the transportblock size and a transport block CRC size.
 8. The method of claim 6,wherein in case that a sum of the transport block size and a transportblock cyclic redundancy check (CRC) size is less than or equal to themaximum code block size, the number of code blocks for the transportblock is determined as
 1. 9. The method of claim 6, wherein in case thata sum of the transport block size and a transport block cyclicredundancy check (CRC) size is greater than the maximum code block size,the number of code blocks for the transport block is determined bydividing a first value by a second value, and wherein the first value isa sum of the transport block size and the transport block CRC size andthe second value is obtained by subtracting a code block CRC size fromthe maximum code block size.
 10. The method of claim 6, furthercomprising performing low density parity check coding (LDPC) for thecode blocks.
 11. A terminal in a wireless communication system, theterminal comprising: a transceiver; and a controller configured to:determine a maximum code block size based on a transport block size andmodulation and coding scheme (MCS) information, determine a number ofcode blocks for the transport block, and segment the transport blockinto the determined number of code blocks.
 12. The terminal of claim 11,wherein the number of code blocks for the transport block is determinedbased on a first value, the maximum code block size, and a code blockcyclic redundancy check (CRC) size, and wherein the first value is a sumof the transport block size and a transport block CRC size.
 13. Theterminal of claim 11, wherein in case that a sum of the transport blocksize and a transport block cyclic redundancy check (CRC) size is lessthan or equal to the maximum code block size, the number of code blocksfor the transport block is determined as
 1. 14. The terminal of claim11, wherein in case that a sum of the transport block size and atransport block cyclic redundancy check (CRC) size is greater than themaximum code block size, the number of code blocks for the transportblock is determined by dividing a first value by a second value, andwherein the first value is a sum of the transport block size and thetransport block CRC size and the second value is obtained by subtractinga code block CRC size from the maximum code block size.
 15. The terminalof claim 11, wherein the controller is further configured to perform lowdensity parity check coding (LDPC) for the code blocks.
 16. A basestation in a wireless communication system, the base station comprising:a transceiver; and a controller configured to: determine a maximum codeblock size based on a transport block size and modulation and codingscheme (MCS) information, determine a number of code blocks for thetransport block, and segment the transport block into the determinednumber of code blocks.
 17. The base station of claim 16, wherein thenumber of code blocks for the transport block is determined based on afirst value, the maximum code block size, and a code block cyclicredundancy check (CRC) size, and wherein the first value is a sum of thetransport block size and a transport block CRC size.
 18. The basestation of claim 16, wherein in case that a sum of the transport blocksize and a transport block cyclic redundancy check (CRC) size is lessthan or equal to the maximum code block size, the number of code blocksfor the transport block is determined as
 1. 19. The base station ofclaim 16, wherein in case that a sum of the transport block size and atransport block cyclic redundancy check (CRC) size is greater than themaximum code block size, the number of code blocks for the transportblock is determined by dividing a first value by a second value, andwherein the first value is a sum of the transport block size and thetransport block CRC size and the second value is obtained by subtractinga code block CRC size from the maximum code block size.
 20. The basestation of claim 16, wherein the controller is further configured toperform low density parity check coding (LDPC) for the code blocks.